1. Field of the Invention
The present invention relates to dish antennas, such as satellite antennas and, in particular, concerns a device and method for reducing the build up of water, frozen or liquid, adjacent the receiving surface of the dish to thereby reduce disruption of the transmission of signals to or from the dish antenna.
2. Description of the Related Art
Dish antennas are antennas that are commonly used for a wide variety of different purposes. For example, large satellite communications antennas both transmit and receive communications from satellites in outer space. Further, the growth of satellite entertainment networks has led to a proliferation of smaller dish shaped receiving antennas that receive signals containing the entertainment from orbiting satellites. Dish-shaped antennas are also used in a wide variety of other communications applications such as microwave transmissions and the like.
While dish shaped antennas are well suited for receiving and transmitting a wide variety of signals, the shape of the antenna leads them to be particularly susceptible to the effects of the build up of water on the antennas. More specifically, dish antennas generally have a concave inner surface where moisture, such as rain, dew, condensation, ice and snow, can accumulate. When sufficient quantities of moisture or water, in either liquid or frozen form, accumulate, the water can disrupt or even completely interrupt the communications of signals to and from the antenna.
To address this problem, various covers have been proposed. For example, U.S. Pat. No. 5,798,735 to Walton provides an example of a particular kind of assembly that is designed to inhibit the accumulation of snow on a dish antenna. In this implementation, the cover extends about the opening that defines the concave inner surface of the dish antenna. The cover is formed of a material, such as polytetrafluoroethylene (PTFE), that allows for the transmission of satellite and other communications signals. The space between the concave inner surface of the dish antenna and the cover can be heated by the introduction of heated air into the space. The heated air then warms the cover and inhibits the accumulation of snow on the outer surface of the cover.
While the system disclosed in U.S. Pat. No. 5,798,735 works well in inhibiting the accumulation of snow and other frozen precipitation on the outer surface of the cover, there are some applications where the introduction of heated air into the air space will be less effective in eliminating or reducing the accumulation of water on the cover. For example, rain, dew or condensation can still accumulate on the outer surface of the cover. Providing heated air into the interior space may not be that effective in reducing this accumulation of this type of moisture. Further, this accumulation of water can also result in the degradation or loss of communications signals with the dish antenna. Also, in some applications, providing heated air into the interior space to reduce the accumulations of frozen precipitation may be costly in terms of energy use.
Hence, there is a need for a system and method of reducing the accumulations of water or moisture, in either frozen or liquid form, on the outer surface of covers of dish antennas. To this end, there is a need for an inexpensive apparatus and method of reducing the accumulation of water on the outer surfaces of covers.